A chord is a group of notes built from one note, the root, by stacking intervals – usually thirds. Every chord type has a formula written in scale degrees of the root’s major scale: a major triad is 1–3–5, a minor triad lowers the third (1–♭3–5), a dominant seventh adds a lowered seventh (1–3–5–♭7). Apply the formula to any root and you have the chord.
The important detail is spelling. Each degree of the formula uses its own letter name, so the third of D♭ major is F (not E♯) and the third of E major is G♯ (not A♭). Correct spelling is what makes a chord readable on the staff and shows its function; that is why the calculator sometimes produces double sharps or flats, such as B♯ and D𝄪 in G♯ augmented or B𝄫 in C diminished 7th – it also lists the simpler enharmonic names that sound the same.
Use it to learn chord construction, check a lead sheet, find voicings on the keyboard or see which notes two chords share before writing a progression.
How to use the Chord Calculator
- Root note
- Chord type
Everything is calculated in your browser, so results appear instantly and nothing you type is sent to a server.
How it works
Choose a root and a chord type. Each formula degree moves the root up the matching number of letter names and the matching number of semitones (a major third is 2 letters and 4 semitones), which gives the correctly spelled note. Accidentals in the formula (♭, ♯) lower or raise a degree by one semitone.
Worked example
A major: the A major scale is A, B, C♯, D, E, F♯, G♯, so degrees 1, 3, 5 give A, C♯, E. C minor: apply 1, ♭3, 5 to C major (C, D, E, F, G, A, B) – lower E to E♭ – and you get C, E♭, G. D♭ diminished 7th (1, ♭3, ♭5, ♭♭7) is D♭, F♭, A𝄫, C𝄫, which sounds like D♭, E, G, B♭.
Chord formulas
| Chord | Symbol (on C) | Formula | Notes on C |
|---|---|---|---|
| Major | C | 1 3 5 | C E G |
| Minor | Cm | 1 ♭3 5 | C E♭ G |
| Augmented | C+ | 1 3 ♯5 | C E G♯ |
| Diminished | C° | 1 ♭3 ♭5 | C E♭ G♭ |
| Sus2 / sus4 | Csus2 / Csus4 | 1 2 5 / 1 4 5 | C D G / C F G |
| Dominant 7th | C7 | 1 3 5 ♭7 | C E G B♭ |
| Major 7th | Cmaj7 | 1 3 5 7 | C E G B |
| Minor 7th | Cm7 | 1 ♭3 5 ♭7 | C E♭ G B♭ |
| Half-diminished | Cø7 | 1 ♭3 ♭5 ♭7 | C E♭ G♭ B♭ |
| Diminished 7th | C°7 | 1 ♭3 ♭5 ♭♭7 | C E♭ G♭ B𝄫 |
| Major 6th | C6 | 1 3 5 6 | C E G A |
| Dominant 9th | C9 | 1 3 5 ♭7 9 | C E G B♭ D |
Formula
Chord notes = root + intervals of the formula, counted on the root’s major scale
Major = 1 3 5 · minor = 1 ♭3 5 · dominant 7th = 1 3 5 ♭7 · diminished 7th = 1 ♭3 ♭5 ♭♭7
Worked example
Inputs — Root note: C; Chord type: Major triad (C).
Results — Chord symbol = C; Notes = C, E, G; Formula (scale degrees) = 1, 3, 5; Intervals above the root = P1, M3, P5; Semitones above the root = 0, 4, 7; Chord name = C major triad.
Key terms
- Root
- The note a chord is built on and named after.
- Triad
- A three-note chord of root, third and fifth.
- Chord quality
- Major, minor, augmented, diminished – set by the sizes of the third and fifth.
- Enharmonic
- Two spellings of the same pitch, such as F♯ and G♭.
- Extension
- Chord tones above the seventh – the 9th, 11th and 13th.
Frequently asked questions
What notes are in a C major chord?
C, E and G – the 1st, 3rd and 5th degrees of the C major scale.
How do I build a minor chord?
Lower the third of the major chord by a semitone: C minor is C, E♭, G (formula 1, ♭3, 5).
What is the difference between C7 and Cmaj7?
C7 (dominant) has a minor seventh, B♭; Cmaj7 has a major seventh, B. C7 wants to resolve to F, Cmaj7 sounds settled.
Why does A major contain C♯ and not D♭?
The third of A must use the letter C (A–B–C), and C raised by a semitone is C♯.
What is a diminished seventh chord?
A stack of minor thirds: 1, ♭3, ♭5, ♭♭7. On C it is C, E♭, G♭, B𝄫 – the B𝄫 sounds like A.
What is a sus4 chord?
The third is replaced by the fourth: Csus4 = C, F, G. It sounds open and usually resolves to the major chord.
How many notes does a 13th chord have?
In theory seven (1, 3, 5, ♭7, 9, 11, 13); in practice the 11th (and often the 5th) is left out, which is how this calculator spells C13: C, E, G, B♭, D, A.